Perhaps this should have been posted in Maintenance? But since my particular interest is the Aztec and its engines, here we are.
During training, should one simulate power failure of an engine with a counter-weighted crank by, [a] moving the throttle to idle or moving the mixture to I.C.O. Which method is least detrimental to the engine? Does it make any difference?
"I have long heard of (and subscribe to) the notion of making smooth (as opposed to 'slam' or 'jerk') power adjustments. Ostensibly so as to not 'detune' the engine. Over time I have come to understand (I think) that refers to the crankshaft counterweights ('dynamic dampers'?)
Stopping for a moment to think about it, I have no idea what 'detuning' means. I know the weights are attached to the crank via pins on a flange. And that the weights have some movement about those pins available in the plane of rotation. The weights are selected or balanced against some rotational harmonic within the engine; not sure how that parameter could change.
I also believe that in a throttle 'slam' event (instantaneous full power or idle selection), inertia plays a role and while the engine may respond quickly, it does not do so instantly. Same thing a full power and moving the Mixture to I.C.O.
On some radial engines reducing the power so that the airstream is driving the prop (engine) is a no-no because of a detrimental effect on the bearings. Not sure if that is in any way applicable to out 'flat' engines?
So, can anyone shed light on the role and operation of the counterweights?
Thanks.
During training, should one simulate power failure of an engine with a counter-weighted crank by, [a] moving the throttle to idle or moving the mixture to I.C.O. Which method is least detrimental to the engine? Does it make any difference?
"I have long heard of (and subscribe to) the notion of making smooth (as opposed to 'slam' or 'jerk') power adjustments. Ostensibly so as to not 'detune' the engine. Over time I have come to understand (I think) that refers to the crankshaft counterweights ('dynamic dampers'?)
Stopping for a moment to think about it, I have no idea what 'detuning' means. I know the weights are attached to the crank via pins on a flange. And that the weights have some movement about those pins available in the plane of rotation. The weights are selected or balanced against some rotational harmonic within the engine; not sure how that parameter could change.
I also believe that in a throttle 'slam' event (instantaneous full power or idle selection), inertia plays a role and while the engine may respond quickly, it does not do so instantly. Same thing a full power and moving the Mixture to I.C.O.
On some radial engines reducing the power so that the airstream is driving the prop (engine) is a no-no because of a detrimental effect on the bearings. Not sure if that is in any way applicable to out 'flat' engines?
So, can anyone shed light on the role and operation of the counterweights?
Thanks.
